In mining minerals, ores, or other material it is often necessary to process the excavated material into more uniform size pieces for transport on conveyors and the like. Because material processing increases the cost of the operations it is imperative that material comminution and transport be as efficient as possible.
In open cut iron ore mines, coal mines, and mineral beneficiating mines huge volumes of material are excavated from a mine face and thereafter transported to a distal storage site, shipping site, or processing site.
Various apparatus and methods for comminuting and transporting excavated materials are known in the prior art. U.S. Pat. Nos. 2,593,353, 3,510,073, 3,752,334, 4,059,195, 4,383,651, 4,491,279, 4,669,674, 4,712,744, 4,721,201, 4,881,691, 5,580,004, 5,797,548, 5,803,376, 5,911,373, 7,278,596 disclose examples of such apparatuses. Such apparatus and typically include a rock crusher, communicating with conveyor systems for crushing and thereafter transporting the material to a location distal from the excavation and crushing site.
Material may be excavated from a mine face using machines such as drag lines, front-end loaders and mechanical shovels. Blasting with explosives may precede excavation. When the distance between the mine face and rock crusher is not overly large, the excavated material may be deposited directly into the rock crusher by the excavating machines. However, as the mine face advances due to continuous excavation and material removal, the distance the excavated material must be transported to the rock crusher increases which necessitates that the excavating machines traverse back and forth between the mine face and the rock crusher. Alternatively, transport vehicles such as dump trucks are employed to traverse the distance between the excavating machines at the mine face and the rock crusher. Unfortunately, as the distance increases efficiency decreases. To address this problem, additional transport vehicles may be employed or the rock crusher may be shut down, disassembled and moved to a position closer to the mine face and then reassembled to decrease transportation distances.
Rock crushers, also called crushing stations, crushing circuits, or sizers, generally comprise a vertical tower structure positioned immediately adjacent a reinforced vertical wall supporting a massive earthen ramp on the side opposite the tower structure. Earth moving vehicles, such as dump trucks loaded with excavated material, travel up the earthen ramp and back-up to a feed orifice at an upper end portion of the tower structure. The material is dumped into the crushing station's feed orifice and thereafter passes through a top size control aperture, also known as a grizzly, and into a rock crushing mechanism which comminutes the material into desirable sized pieces. The crushed material exits the crushing station through a lower discharge orifice spacedly below the feed orifice onto a conveyor for transfer to another site.
Relocation of a crushing station is an enormous and expensive undertaking requiring that a new reinforced vertical retaining wall and earthen ramp be built, at least partial disassembly of the tower structure, the loading of the tower structure and associated components on vehicles, the transport of the tower structure and components to the new location and reassembly. Auxiliary equipment, apparatus and facilities such as electrical generation stations, fuel tanks, access roads (entry and exit) and the like must also be relocated and perhaps constructed. During the relocation process the entire crushing station must be shut down, effectively stopping production of the entire mine and further decreasing efficiency.
Crushing stations, by their very nature are subject to significant amounts of “wear and tear” during normal operating conditions and require regular maintenance. Shutting down a crushing station so that it may be moved materially adds to the amount of unavoidable down time caused by foreseeable repair and maintenance. Such additional “down time” further increases costs and inefficiency and may make a project economically not viable.
There is a need for a system that can increase the efficiency of material comminution and transport for material excavation without incurring substantial costs of additional transport equipment such as additional dump trucks, or significant construction needs such as retaining wall and earthen ramp construction. Preferably, the system is configured to substantially reduce, if not eliminate, downtime caused by shutting down, disassembling, moving and reassembling a crushing station and its associated components, apparatus and facilities used in the comminution and transport of excavated material.